Literature context: o Fisher Scientific Cat# A11006 RRID:AB_141373) were used to detect immune com
Breast cancer is the most commonly diagnosed malignancy in women. Analysis of breast cancer genomic DNA indicates frequent loss-of-function mutations in components of the cJUN NH2-terminal kinase (JNK) signaling pathway. Since JNK signaling can promote cell proliferation by activating the AP1 transcription factor, this apparent association of reduced JNK signaling with tumor development was unexpected. We examined the effect of JNK deficiency in the murine breast epithelium. Loss of JNK signaling caused genomic instability and the development of breast cancer. Moreover, JNK deficiency caused widespread early neoplasia and rapid tumor formation in a murine model of breast cancer. This tumor suppressive function was not mediated by a role of JNK in the growth of established tumors, but by a requirement of JNK to prevent tumor initiation. Together, these data identify JNK pathway defects as 'driver' mutations that promote genome instability and tumor initiation.
Literature context: at# A11006; RRID:AB_141373 anti-rat Alexa 546 Invitrogen C
The murine embryonic blood-brain barrier (BBB) consists of endothelial cells (ECs), pericytes (PCs), and basement membrane. Although PCs are critical for inducing vascular stability, signaling pathways in PCs that regulate EC morphogenesis during BBB development remain unexplored. Herein, we find that murine embryos lacking the transforming growth factor β (TGF-β) receptor activin receptor-like kinase 5 (Alk5) in brain PCs (mutants) develop gross germinal matrix hemorrhage-intraventricular hemorrhage (GMH-IVH). The germinal matrix (GM) is a highly vascularized structure rich in neuronal and glial precursors. We show that GM microvessels of mutants display abnormal dilation, reduced PC coverage, EC hyperproliferation, reduced basement membrane collagen, and enhanced perivascular matrix metalloproteinase activity. Furthermore, ALK5-depleted PCs downregulate tissue inhibitor of matrix metalloproteinase 3 (TIMP3), and TIMP3 administration to mutants improves endothelial morphogenesis and attenuates GMH-IVH. Overall, our findings reveal a key role for PC ALK5 in regulating brain endothelial morphogenesis and a substantial therapeutic potential for TIMP3 during GMH-IVH.
Literature context: body (Thermo Fisher Cat# A11006 RRID:AB_141373), and counter-stained with 2-(4
Involution returns the lactating mammary gland to a quiescent state after weaning. The mechanism of involution involves collapse of the mammary epithelial cell compartment. To test whether the cJUN NH2-terminal kinase (JNK) signal transduction pathway contributes to involution, we established mice with JNK deficiency in the mammary epithelium. We found that JNK is required for efficient involution. JNK deficiency did not alter the STAT3/5 or SMAD2/3 signaling pathways that have been previously implicated in this process. Nevertheless, JNK promotes the expression of genes that drive involution, including matrix metalloproteases, cathepsins, and BH3-only proteins. These data demonstrate that JNK has a key role in mammary gland involution post lactation.
Literature context: ermo Fisher Scientific, MA, USA RRID:AB_141373 1:400
The fruit fly can evaluate its energy state and decide whether to pursue food-related cues. Here, we reveal that the mushroom body (MB) integrates hunger and satiety signals to control food-seeking behavior. We have discovered five pathways in the MB essential for hungry flies to locate and approach food. Blocking the MB-intrinsic Kenyon cells (KCs) and the MB output neurons (MBONs) in these pathways impairs food-seeking behavior. Starvation bi-directionally modulates MBON responses to a food odor, suggesting that hunger and satiety controls occur at the KC-to-MBON synapses. These controls are mediated by six types of dopaminergic neurons (DANs). By manipulating these DANs, we could inhibit food-seeking behavior in hungry flies or promote food seeking in fed flies. Finally, we show that the DANs potentially receive multiple inputs of hunger and satiety signals. This work demonstrates an information-rich central circuit in the fly brain that controls hunger-driven food-seeking behavior.
Literature context: , Life Technologies Cat#A11006, RRID:AB_141373 Alexa 647 Goat Anti-Mouse IgG (
Microtubules are essential for polarized transport in neurons, but how their organization guides motor proteins to axons or dendrites is unclear. Because different motors recognize distinct microtubule properties, we used optical nanoscopy to examine the relationship between microtubule orientations, stability, and modifications. Nanometric tracking of motors to super-resolve microtubules and determine their polarity revealed that in dendrites, stable and acetylated microtubules are mostly oriented minus-end out, while dynamic and tyrosinated microtubules are oriented oppositely. In addition, microtubules with similar orientations and modifications form bundles that bias transport. Importantly, because the plus-end-directed Kinesin-1 selectively interacts with acetylated microtubules, this organization guides this motor out of dendrites and into axons. In contrast, Kinesin-3 prefers tyrosinated microtubules and can enter both axons and dendrites. This separation of distinct microtubule subsets into oppositely oriented bundles constitutes a key architectural principle of the neuronal microtubule cytoskeleton that enables polarized sorting by different motor proteins.
Literature context: y (Molecular Probes Cat# A11006 RRID:AB_141373) and counterstained with 2-(4-a
Developmental morphogenesis, tissue injury, and oncogenic transformation can cause the detachment of epithelial cells. These cells are eliminated by a specialized form of apoptosis (anoikis). While the processes that contribute to this form of cell death have been studied, the underlying mechanisms remain unclear. Here, we tested the role of the cJUN NH2-terminal kinase (JNK) signaling pathway using murine models with compound JNK deficiency in mammary and kidney epithelial cells. These studies demonstrated that JNK is required for efficient anoikis in vitro and in vivo. Moreover, JNK-promoted anoikis required pro-apoptotic members of the BCL2 family of proteins. We show that JNK acts through a BAK/BAX-dependent apoptotic pathway by increasing BIM expression and phosphorylating BMF, leading to death of detached epithelial cells.
Literature context: (AF488) Invitrogen Cat# A11006; RRID:AB_141373 Goat anti-rabbit (AF488) Invitr
Clearance of apoptotic cells (ACs) by phagocytes (efferocytosis) prevents post-apoptotic necrosis and dampens inflammation. Defective efferocytosis drives important diseases, including atherosclerosis. For efficient efferocytosis, phagocytes must be able to internalize multiple ACs. We show here that uptake of multiple ACs by macrophages requires dynamin-related protein 1 (Drp1)-mediated mitochondrial fission, which is triggered by AC uptake. When mitochondrial fission is disabled, AC-induced increase in cytosolic calcium is blunted owing to mitochondrial calcium sequestration, and calcium-dependent phagosome formation around secondarily encountered ACs is impaired. These defects can be corrected by silencing the mitochondrial calcium uniporter (MCU). Mice lacking myeloid Drp1 showed defective efferocytosis and its pathologic consequences in the thymus after dexamethasone treatment and in advanced atherosclerotic lesions in fat-fed Ldlr-/- mice. Thus, mitochondrial fission in response to AC uptake is a critical process that enables macrophages to clear multiple ACs and to avoid the pathologic consequences of defective efferocytosis in vivo.
Literature context: ar Probes CAT# A11006; RRID:AB_141373 Goat anti-Rat Alexa 594 Molecul
The generation of precise synaptic connections between developing neurons is critical to the formation of functional neural circuits. Astrocyte-secreted glypican 4 induces formation of active excitatory synapses by recruiting AMPA glutamate receptors to the postsynaptic cell surface. We now identify the molecular mechanism of how glypican 4 exerts its effect. Glypican 4 induces release of the AMPA receptor clustering factor neuronal pentraxin 1 from presynaptic terminals by signaling through presynaptic protein tyrosine phosphatase receptor δ. Pentraxin then accumulates AMPA receptors on the postsynaptic terminal forming functional synapses. Our findings reveal a signaling pathway that regulates synaptic activity during central nervous system development and demonstrates a role for astrocytes as organizers of active synaptic connections by coordinating both pre and post synaptic neurons. As mutations in glypicans are associated with neurological disorders, such as autism and schizophrenia, this signaling cascade offers new avenues to modulate synaptic function in disease.
Literature context: Life Technologies Cat# A11006; RRID:AB_141373 Alexa Fluor 546 Goat anti-Rabbi
Concomitant hepatocyte apoptosis and regeneration is a hallmark of chronic liver diseases (CLDs) predisposing to hepatocellular carcinoma (HCC). Here, we mechanistically link caspase-8-dependent apoptosis to HCC development via proliferation- and replication-associated DNA damage. Proliferation-associated replication stress, DNA damage, and genetic instability are detectable in CLDs before any neoplastic changes occur. Accumulated levels of hepatocyte apoptosis determine and predict subsequent hepatocarcinogenesis. Proliferation-associated DNA damage is sensed by a complex comprising caspase-8, FADD, c-FLIP, and a kinase-dependent function of RIPK1. This platform requires a non-apoptotic function of caspase-8, but no caspase-3 or caspase-8 cleavage. It may represent a DNA damage-sensing mechanism in hepatocytes that can act via JNK and subsequent phosphorylation of the histone variant H2AX.
Literature context: exa488/594/647 Molecular Probes RRID:AB_141373 / RRID: AB_141374 / RRID: AB_14
The conserved polarity effector proteins PAR-3, PAR-6, CDC-42, and atypical protein kinase C (aPKC) form a core unit of the PAR protein network, which plays a central role in polarizing a broad range of animal cell types. To functionally polarize cells, these proteins must activate aPKC within a spatially defined membrane domain on one side of the cell in response to symmetry-breaking cues. Using the Caenorhabditis elegans zygote as a model, we find that the localization and activation of aPKC involve distinct, specialized aPKC-containing assemblies: a PAR-3-dependent assembly that responds to polarity cues and promotes efficient segregation of aPKC toward the anterior but holds aPKC in an inactive state, and a CDC-42-dependent assembly in which aPKC is active but poorly segregated. Cycling of aPKC between these distinct functional assemblies, which appears to depend on aPKC activity, effectively links cue-sensing and effector roles within the PAR network to ensure robust establishment of polarity.
Literature context: Fluor 488 Invitrogen A11006 RRID:AB_141373 Brain Clausen BH, et al. J Ne
Cellular senescence, defined as an irreversible cell cycle arrest, exacerbates the tissue microenvironment. Our previous study demonstrated that mouse uterine senescent cells were physiologically increased according to gestational days and that their abnormal accumulation was linked to the onset of preterm delivery. We hypothesized that there is a mechanism for removal of senescent cells after parturition to maintain uterine function. In the current study, we noted abundant uterine senescent cells and their gradual disappearance in wild-type postpartum mice. F4/80+ macrophages were present specifically around the area rich in senescent cells. Depletion of macrophages in the postpartum mice using anti-F4/80 antibody enlarged the area of senescent cells in the uterus. We also found excessive uterine senescent cells and decreased second pregnancy success rate in a preterm birth model using uterine p53-deleted mice. Furthermore, a decrease in F4/80+ cells and an increase in CD11b+ cells with a senescence-associated inflammatory microenvironment were observed in the p53-deleted uterus, suggesting that uterine p53 deficiency affects distribution of the macrophage subpopulation, interferes with senescence clearance, and promotes senescence-induced inflammation. These findings indicate that the macrophage is a key player in the clearance of uterine senescent cells to maintain postpartum uterine function.
Literature context: #A-11006; RRID:AB_141373 Anti-mouse
Aberrant activation of the SRC family kinase hematopoietic cell kinase (HCK) triggers hematological malignancies as a tumor cell-intrinsic oncogene. Here we find that high HCK levels correlate with reduced survival of colorectal cancer patients. Likewise, increased Hck activity in mice promotes the growth of endogenous colonic malignancies and of human colorectal cancer cell xenografts. Furthermore, tumor-associated macrophages of the corresponding tumors show a pronounced alternatively activated endotype, which occurs independently of mature lymphocytes or of Stat6-dependent Th2 cytokine signaling. Accordingly, pharmacological inhibition or genetic reduction of Hck activity suppresses alternative activation of tumor-associated macrophages and the growth of colon cancer xenografts. Thus, Hck may serve as a promising therapeutic target for solid malignancies.
Literature context: 41693; AB_141373; RRID:AB_1
Apical constriction is a widely utilized cell shape change linked to folding, bending and invagination of polarized epithelia. It remains unclear how apical constriction is regulated spatiotemporally during tissue invagination and how this cellular process contributes to tube formation in different developmental contexts. Using Drosophila salivary gland (SG) invagination as a model, we show that regulation of folded gastrulation expression by the Fork head transcription factor is required for apicomedial accumulation of Rho kinase and non-muscle myosin II, which coordinate apical constriction. We demonstrate that neither loss of spatially coordinated apical constriction nor its complete blockage prevent internalization and tube formation, although such manipulations affect the geometry of invagination. When apical constriction is disrupted, compressing force generated by a tissue-level myosin cable contributes to SG invagination. We demonstrate that fully elongated polarized SGs can form outside the embryo, suggesting that tube formation and elongation are intrinsic properties of the SG.
Literature context: ed goat anti-ratMolecular ProbesCat#A-11006Alexa Fluor 568-conjugated goat
Mutations in mtDNA lead to muscular and neurological diseases and are linked to aging. The most frequent aberrancy is the "common deletion" that involves a 4,977-bp region flanked by 13-bp repeats. To investigate the basis of this deletion, we developed a single-molecule mtDNA combing method. The analysis of replicating mtDNA molecules provided in vivo evidence in support of the asymmetric mode of replication. Furthermore, we observed frequent fork stalling at the junction of the common deletion, suggesting that impaired replication triggers the formation of this toxic lesion. In parallel experiments, we employed mito-TALENs to induce breaks in distinct loci of the mitochondrial genome and found that breaks adjacent to the 5' repeat trigger the common deletion. Interestingly, this process was mediated by the mitochondrial replisome independent of canonical DSB repair. Altogether, our data underscore a unique replication-dependent repair pathway that leads to the mitochondrial common deletion.
Literature context: A-11006; RRID:AB_141373), Alexa Fl
Cell adhesion molecules play important roles in the development of the nervous system. Among the contactin-associated protein (Caspr; also known as Cntnap) family, which belongs to the neurexin superfamily of proteins, Caspr and Caspr2 are indispensable for the formation and maintenance of myelinated nerves. In contrast, a physiological role for Caspr3 remains to be elucidated. This study examines the expression and localization of Caspr3 in the mouse brain using newly generated Caspr3 antibodies. Caspr3 was expressed abundantly between the first and the second postnatal weeks. During this period, Caspr3 was localized especially to the basal ganglia, including the striatum, external segment of the globus pallidus, and substantia nigra, and no gross abnormalities were apparent in the basal ganglia of Caspr3 knockout mice. In the striatum, Caspr3 was expressed by a subpopulation of medium spiny neurons that constitute the direct and indirect pathways. Caspr3 immunostaining was observed as punctate around the cell bodies as well as in the soma. These Caspr3 signals did not, however, overlap with those of synaptic markers. Our findings suggest that Caspr3 may play an important role in basal ganglia development during early postnatal stages.
Literature context: # A11006, RRID:AB_141373) and goat
The phylogenetic position of the phylum Ctenophora and the nature of ctenphore nervous systems are highly debated topics in modern evolutionary biology. However, very little is known about the organization of ctenophore neural and muscular systems, and virtually nothing has been reported about their embryogenesis. Here we have characterized the neural and muscular development of the sea gooseberry, Pleurobrachia bachei, starting from the cleavage stages to posthatching larvae. Scanning electron microscopy and immunochemistry were used to describe the formation of the embryonic mouth, tentacles, combs, aboral organ, and putative sensory cells. The muscles started their specification at the end of the first day of Pleurobrachia development. In contrast, neurons appeared 2 days after myogenesis, just before the hatching of fully formed cydippid larvae. The first tubulin-immunoreactive neurons, a small group of four to six cells with neuronal processes, was initially recognized at the aboral pole during the third day of development. Surprisingly, this observed neurogenesis occurred after the emergence of distinct behavioral patterns in the embryos. Thus, the embryonic behavior associated with comb cilia beatings and initial muscle organization does not require morphologically defined neurons and their elongated neurites. This study provides the first description of neuromuscular development in the enigmatic ctenophores and establishes the foundation for future research using emerging genomic tools and resources.